1. Field of the Invention
This invention relates to a refractory runner and a method of constructing a refractory runner and more particularly to a trough associated with a blast furnace for the conveyance of molten iron from the blast furnace into a trough formed by a plurality of refractory side blocks forming opposed side walls and a base or floor formed by compacting particulate refractory material between the opposed side walls.
2. Description of the Prior Art
In the manufacture of pig iron the molten iron flows through an iron notch in the hearth of a blast furnace into a main trough that is built on the floor of the cast house in the blast furnace plant. The molten iron flows down the trough or runner under a skimmer located near the end of the main trough. The skimmer separates any slag or cinder flowing with the iron and diverts the slag into the cinder ladles or to the cinder granulating pit. The molten iron continues to flow down the main trough. At selected intervals, branch troughs extend in various directions from the main trough. Gates or shutters located at the intersection of the main trough and the branch troughs divert the molten iron from the main trough into the respective branch troughs. The molten iron then flows through the branch troughs into iron ladles.
The main trough and branch troughs are emptied after each cast. After each cast, the runners must be carefully cleaned of both metal and slag. The side walls and floor of the trough are brushed with a thick clay or loam slurry, which when dry, protects the trough to prevent iron from sticking to the side walls and floor.
The trough has a generally U-shaped configuration formed by substantially upstanding side walls and a base or floor connected the lower ends of the side walls. It is known to construct a cast house trough or runner by firebrick forming the side walls and floors. However, the brick is subject to the deleterious effects of the molten iron and slag. After a period of time, the firebrick becomes damaged and must be replaced. Repair of a brick runner is a very time consuming task and removes the entire runner from operation during the period of repair.
Another form of cast house runner construction includes a steel plate trough base. The steel plate base is lined with firebrick and a carbon brick facing is placed next to the firebrick. This is known as a carbon-lined trough. The carbon brick is plastered with clay before cast time in order to prevent the carbon from oxidizing during the cast.
More recently, cast house runners have been fabricated of individual precast refractory trough sections. Each section has a substantially U-shaped configuration formed by a pair of oppositely positioned side walls connected at their lower end portions by a base or floor to form a unitary structure that includes integral side walls and floor. The U-shaped trough has a preselected length, width and height. The upper horizontal edges of the side walls are provided with lift points by which the trough section is secured to permit the section to be raised and lowered into and out of position relative to adjacent trough sections.
Damage and wear of a cast house runner generally occurs at the base or floor of the runner. For a runner constructed of refractory brick, the damaged brick must be removed and replacement brick inserted. For a runner constructed of a plurality of individual precast refractory trough sections, the particular section containing the damaged base must be removed. Consequently, if only a portion of the base of a trough section is damaged, the entire trough section must be removed and replaced even though a limited portion of the trough section is damaged. This requires maintaining a substantial inventory of trough sections. It is also necessary with this arrangement to construct a substantial number of trough sections having a preselected configuration to form the intersections of the main runner with the branch runners.
In addition whenever a trough section is removed and a replacement trough section inserted, the floor of the replacement section must be aligned with the floor of the adjacent sections. This is difficult in many instances where the floor of the undamaged adjacent trough sections has become warped after being exposed to many casts. Another obvious disadvantage of this type of runner construction is the downtime required to remove a damaged trough section and install and level the replacement trough section.
While it is known to provide replaceable runner sections in a cast house, the known runner constructions are not efficiently repaired. The known types of runner constructions require a large inventory of replacement components. The repair is time consuming and constitutes an interference in the operation of the blast furnace. Therefore, there is need for a runner construction that is easily assembled by components that are substantially uniform in construction thereby minimizing the number of component configurations required to be maintained in inventory and permitting repairs to be made without removing undamaged components.